Humidifier control

ABSTRACT

A control unit for a humidification system using steam as the air moistening agent. The unit includes a closed chamber for lowpressure exit steam located within a closed chamber for highpressure entry steam to assure that the exiting steam is dry or superheated. A slide valve located in the entry steam chamber opens and closes a port between the two chambers in response to the moisture condition in a space being humidified by steam from the control unit.

United States Patent Potchen 1 Feb. 15,1972

[54] HUMIDIFIER CONTROL [72] Inventor: Peter F. Potchen, Brooklyn, Ohio [73] Assignee: The Clark-Reliance Corp., Cleveland,

Ohio

[22] Filed: Aug. 5, 1969 [21] Appl. No.: 847,609

[52] U.S. Cl. ,.236/44 A, 137/193, 251/326, 261/ 1 17 [51] Int. Cl. ..B0lf 3/02 [58] Field of Search ..236/44 A; 137/193; 251/326; 261/ 1 17 [56] References Cited I UNITED STATES PATENTS 234,095 11/1880 Wallace ..137/193 1,039,340 9/1912 Weitzel ..251/326 1,729,074 9/ 1929 Karlson ..236/44 A 2,051,484 8/1936 Jordan ...25l/326 X 2,213,167 8/1940 Marsh..... 236/44 A 2,314,892 3/1943 Papu|ski.. 236/44 A 2,650,616 9/1953 Wilkinson et a1. ..251/326 X 2,809,657 10/1957 Stephenson ..251/326 X Primary Examiner-Tim R. Miles [57] ABSTRACT A control unit for a humidification system using steam as the air moistening agent. The unit includes a closed chamber for low-pressure exit steam located within a closed chamber for high-pressure entry steam to assure that the exiting steam is dry or superheated. A slide valve located in the entry steam chamber opens and closes a port between the two chambers in response to the moisture condition in a space being humidified by steam from the control unit.

7 Claims, 3 Drawing Figures PMENTEBFEB 15 I972 3.642.201

SHEET 1 [1F 2 28 FLOW F A DRAIN INVENTOR. PETER F. POTCHEN din ATTORNEYS PATENIEDFEB 15 I972 3.642.201

sum 2 [IF 2 ,INVENTOR. PETER F. POTCHEN 3W, 5W J/mdham 65 6am ATTORNEYS BACKGROUND OF THE INVENTION This invention relates to humidification systems using steam as the air moistening agent and especially to the control of the moisture level in the space in which steam is being dispersed to moisten the atmosphere. More particularly the invention relates to a control unit which serves both to superheat the low-pressure steam being dispersed so as to assure that the steam is in a dry or unsaturated condition and also to meter the dispersion of the steam in response to the moisture condition in the space being humidified.

I-Iumidification systems which use steam to moisten the air require careful handling and control of the steam supply to minimize moisture accumulation and damage due to a wet vapor condition or in other words a pressure-temperature condition below the point of saturation. Accordingly, it is particularly important that the steam being dispersed be in a dry or superheated condition so that water droplets will not be discharged from the control unit and disperser unit to cause corrosion damage. For this reason it is common practice to pass the low-pressure steam exiting the control unit through a high-pressure chamber or jacket to assure a dry or superheated condition when the steam reaches the disperser.

In order to control the amount of steam passing through the steam disperser and thus control the amount of moisture in the space being humidified,it is desirable to have a valve located between the steam jacket or high-pressure entry chamber, and the low-pressure steam exit chamber. The position of the valve has most commonly been controlled by pneumatic pressure and the pressure has been responsive to the moisture condition in the space being humidified by the system.

Prior art valves for this purpose have been of the ball or globe type and have been subject to malfunction and rapid wear. A typical example of a prior art control valve is shown in US. Pat. No. 2,314,892, to Papulski. Such valves require positive external force (such as air pressure) both to move the valve and to properly seal it in its seat.

Also, prior art valves of this type inherently have only two operating positions-fully open and fully closed. They are not capable of modulating the supply of steam according to the humidity condition of the air being moistened.

The valve in the control unit of the present invention, however, reduces the difficulties indicated above and affords other features and advantages not obtainable from the prior art.

SUMMARY OF THE INVENTION It is among the objects of the invention to control with improved reliability, the supply of steam to a steam disperser in a humidification system which uses the steam as the air moistening agent.

Another object is to provide an improved airor solenoidoperated valve for a control unit in a steam dispersing humidification system, which utilizes steam pressure to assist in sealing the valve when in its closed position.

Still another object is to provide a control unit that is capable of modulating the release of steam by a humidification system utilizing steam as the moistening agent, to maintain a uniform humidity condition in the air being moistened by the system.

These and other objects are accomplished by means of a control unit connected between a steam supply and a steam disperser and which comprises an outer casing defining an entry chamber for steam at high pressure and an inner casing within the outer casing which defines a lower-pressure steam exit chamber communicating with the steam disperser. The inner casing has a valve port communicating between the inlet chamber and the outlet chamber, the port being selectively opened and closed by means of a valve slide adapted for linear travel in the high-pressure entry chamber and which slides across the port between open and closed positions respectively. The valve slide is operated, for example, by a fluid pressure system and the pressure is normally responsive to the humidity condition in the space being moistened by steam from the disperser.-

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view in somewhat diagrammatic form showing a steam dispersing humidification system with a control unit embodying the invention;

FIG. 2 is a cross-sectional view on an enlarged scale of the control unit of FIG. 1 with the valve slide in the closed position; and

FIG. 3 is a cross-sectional view taken on the line 3-3 of FIG. 2 showing the valve slide in its fully open position.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring more particularly to the drawings, FIG. 1 shows a steam dispersing humidification system adapted for use in connection with a forced air type central heating system. The system is adapted to moisten warm air being supplied to an enclosed space and includes a fluid operated control unit A connected between a steam supply line B and a steam disperser C. The control unit A receives steam from the steam supply line B and the steam disperser C is positioned within an air duct 10. The disperser C includes a heating jacket 11 which circulates hot steam from the main steam line B around a central outlet pipe 12. The outlet pipe 12 of the disperser C has dispersion holes 13 formed therein facing counter to the direction of airflow through the air duct 10. Thus, the steam emitted from the disperser C mixes with and is carried by the air in the form of water vapor and thus moistens the air in the space being humidified. The jacket 1 1 serves to assure that the steam in the outlet pipe 12 remains dry or superheated until it passes into the airflow. The release of steam from the highpressure steam supply line B through the Control unit A to the disperser C is responsive to the relative humidity in the atmosphere within the space being humidified. A conventional humidistat 15 is used to monitor the amount of moisture and to relay the information to the control unit A.

Referring to FIG. 2 which shows the construction and operation of the control unit A, there is shown a generally cylindrical outer casing comprising a lower section 20 and an upper section 21. The lower section 20 is open at the bottom but has a bottom plate 22 secured thereto by machine screws 23. The bottom plate 22 has a drain fitting 24 which is opened in a manner to be described more particularly below.

The upper section 21 has an open top covered by a top plate 25 fastened to the upper section 21 by machine screws 26. The lower section 20 and upper section 21 are bolted together and define a high-pressure steam entry chamber 27. The steam enters the chamber 27 through an inlet fitting 28 after passing through the steam jacket 11 which is connected to the main steam line B. The upper section 21 also has an inner wall 29 which is supported within the outer wall of the upper section 21 by spider-type radial spacer arms 30. The inner wall 29 is spaced from the adjacent walls of the lower section 20 and upper section 21 which define the high pressure steam entry chamber 27 and thus is located entirely within the entry chamber 27.

The wall 29 defines a lower pressure steam exit chamber 31 and steam admitted to the chamber 31 exits through a packing gland 32 which connects to the outlet pipe 12 of the steam disperser C. The top of the exit chamber 31 is closed by a valve body 33 bolted to the inner wall 29 by machine screws 34 while the bottom of the chamber 31 has a threaded drain opening which is closed by a pipe plug 35. The valve body 33 has a central port 36 extending therethrough, the lower portion of which is threaded and receives a central pipe 37.

The inner wall 29 also has at its lower portion an inwardly extending annular flange 38 with its circular inner edge spaced from the pipe 37. Surrounding the pipe 37 is a cylindrical perforate filter screen 40 with its upper end supported and sealed between the valve body 33 and the inner wall 29 and its lower end secured to the inner edge of flange 38. The filter screen 40 separates the chamber 31 generally into two parts, one part being the space below and within the screen 40 and the other being the annular space lying between the screen 40 and the inner wall 29 of the upper section 21. The screen serves both to muffle sound and to trap moisture particles which may be entrained in the steam and, in the embodiment shown, is formed of a perforated stainless steel screen inner sleeve and a woven asbestos outer sleeve 39. It will be seen that all of the steam which enters the chamber 11 through the port 36 must pass through the filter screen 40 before exiting through the outlet fitting 32. Another filter screen 41 in the form of a ring of stainless steel wool is located between the outer wall of the upper section 21 and the inner wall 29 to catch moisture particles entrained in the steam entering the chamber 27 and also to muffle sound.

Since the exit chamber 31 is surrounded by the entry chamber 27 which receives the steam at a relatively high pressure from the steam supply line B, the exit steam will tend to be heated as it enters the exit chamber 31 and this combined with the reduced pressure in the exit chamber helps maintain the steam in a superheated or dry condition.

The passage of steam from the entry chamber 27 to the exit chamber 31 through the port 36 is controlled by a slide valve assembly which includes an orifice frame 44 and an orifice disc 45, both located on top of the valve body 33 and concentric with the port 36. The frame 44 and disc 45 are formed, for example, of stainless steel to accommodate wear and to be relatively free from corrosion. The orifice disc 45 has a central port 46 which is opened or closed by a valve slide 47 which is moved to various positions between its fully open position and its fully closed position over the port 46 by a pneumatic operating unit D. Alternatively, a solenoid-type operating unit may be used or in rare instances an electric motor.

The operating unit D includes a casing 50 fastened with two set screws to a smooth boss 49 formed near the top of the upper section 21. The opposite end of the casing 50 is closed by a matching end cap 51, the casing 50 and cap 51 to secured in one another by machine bolts 52. The end cap 51 has a central tapered threaded fitting 53 connected to an air pressure line which is responsive to the humidistat within the space being humidified.

Located within the cylindrical chamber defined by the casing 50 and cap 51 is a piston 54 secured to an operating rod 55. The rod 55 extends through a tension adjusting bushing 56 threaded into an axial opening in the casing 50 and also through a threaded packing sleeve 57 received in the boss 49. The piston 54 is connected to a flexible bellows or rolling diaphragm 58 of annular form which has its outer edges secured between the casing 50 and cap 51 so that the spaces on opposite sides of the piston 54 are sealed off from one another. Accordingly, air entering through the fitting 53 will force the piston 54 to the left, depending on the pressure, as far as shown in FIG. 3 or in other words a position where the port 46 is fully open. The piston 54 is spring loaded to the position shown in FIG. 2 (valve closed position) by means of a helical spring 59 which is tensioned by the threaded bushing 56. The forward end of the casing 50 is open at the sides (FIG. 3) so the tension adjusting bushing 56 may be turned to adjust the spring tension without any disassembly of the operating unit D. The operating rod 55 extends across the upper end of the upper section 21 to a guide bore 60 formed in the opposite side of the upper section 21 of the outer casing and the axial movement of the rod is limited by an adjusting screw 61.

A sleeve 62 is received on the rod 55 between its ends, the sleeve being secured in a predetermined position by jam nuts. A pin 63 extends radially from the sleeve 62 and is received in a suitable slot or bore in the valve slide 47. Accordingly, movement of the operating rod 55 by the piston 54 will determine the position of the valve slide 47 and thus whether or not the valve port 46 is open or closed or at an intermediate position. The position of the piston 54 in turn is responsive to the air pressure which is controlled by the humidistat in the space being heated and humidified. Accordingly, when the humidity ext.

is at a higher level than desired, the valve slide 47 will be in its closed position (FIG. 2) and no steam will be supplied to the steam disperser C. The relatively high steam pressure in the steam entry chamber 27 helps to seal the valve slide 47 in this closed position to prevent leakage of steam into the relatively low-pressure exit chamber 31. I

When the humidity is below a desired level, however, the valve slide 47 will be moved to the left to a partially open position to modulate the supply of steam to the exit chamber 31 and thus maintain the desired moisture level. Where the moisture level is much too low, however, the humidistat will supply enough air pressure to move the valve slide to a relatively wide open position (FIG. 3) to put as much steam as possible into the disperser C until the condition is corrected.

A float valve is mounted on the bottom plate 22 in the steam entry chamber 27, to open and close the passage through the drain fitting 24. The valve hasa head 64 positioned over a drain orifice 65 formed in an orifice bushing in the bottom plate 22. The valve head 64 is moved vertically between open and closed positions by a lever 66 pivotally connected at one end to mounting brackets 67 on the bottom plate 22. The lever 66 has a float 68 at the other end and the float urges the lever upward when sufficient condensate accumulates in the bottom of the steam entry chamber 27.

When the buoyant force is sufficient, the lever raises the valve head 64 from its closed position (FIG. 2) and the condensate drains out or is forced out by steam pressure until the level of condensate drops enough to lower the float 68 and lever 66 and thus moves the head 64 again to its close position. This arrangement eliminates the need for a separate steam trap, however, the unit A must be mounted in a generally vertical position to achieve the desired result.

OPERATION Considering the control unit A of the invention as being installed in the humidification system of, FIG. 1, the operation may be described with respect to an atmospheric condition in the space being heated and humidified, wherein the moisture content of the air is below the desired humidity level. A humidistat located within the space detects the low-moisture condition in the atmosphere and accordingly causes a relatively high-pressure condition to exist in the air operating system for the control unit A. Accordingly, the pressure will force the piston 54 to the left as viewed in FIG. 2 and thus move the valve slide 47 to the left to a position wherein steam from the entry chamber 27 is permitted to pass through the port 46 and thence through the cylindrical filter screen 40. During this passage, the steam assumes a lower pressure condition within the exit chamber but is heated by the high-pressure steam in the surrounding entry chamber 27 so that the exiting steam is in a dry or superheated condition. In other words, the exiting steam remains unsaturated so that moisture particles will not tend to form. In any event, if such particles do form, they will be picked up by the .filter screen 40. The many sudden changes in direction which the steam flow must make during its passage through the unit A also help to remove entrained moisture particles.

The exiting steam then passes through the packing gland 32 and into the outlet pipe 12 of the steam disperser C where its dry or superheated condition is maintained by the high pressure steam in the surrounding steam jacket 11. The steam in the outlet pipe 12 is emitted through the openings 13 and dispersed in the warm air flowing through the duct 10. The continued emission of steam moistens the warm air in the duct 10 which in turn moistens the air in the space being heated and humidified until the humidity reaches a desired level. When this occurs the humidistat will reduce the pressure in the air operating line and the helical spring 59 will force the piston 54 to the right toward the position shown in FIG. 2 and in doing so will move the valve slide 47 either to a fully closed position over the port 46 or to a partially closed position to modulate the escape of steam and thus to maintain the desired moisture level. The high pressure in the entry chamber 27 will help force the valve slide 47 into sealing engagement in its seat and thus help to prevent leakage of steam into the exit chamber.

The unit A may be adjusted before or during operation by turning the adjusting bushing 56 to vary the tension in the helical spring 59. By varying the spring tension, the area of the opening in between the valve slide 47 and port 46 may be adjusted so as to increase or decrease the rate of steam dispersion for a particular pneumatic pressure acting on the piston 54. The maximum size of the opening between the valve slide 47 and port 46 may be adjusted by means of the adjusting screw 61. The screw 61 limits the axial movement of the operating rod 55 in a direction tending to open the valve.

While the invention has been illustrated and described with respect to a specific embodiment thereof this is intended for the purpose of illustration rather than limitation and other forms and modifications will be apparent to those skilled in the art upon a reading of the specification and appended claims. Wherefore the patent is not to be limited in any way that is inconsistent with the extent to which the progress in the art has been advanced by the invention.

lclaim:

l. A device for controlling steam passage from a steam supply line to a steam disperser in a humidification system, comprising an outer casing defining a high-pressure steam entry chamber communicating with a steam supply, an inner casing within said entry chamber and defining a lower pressure steam exit chamber communicating with the steam disperser, said inner casing having a valve port communicating between said inlet chamber and said exit chamber, a valve slide adapted for linear movement in said entry chamber to open and close said port, humidistat means for sensing the humidity in an area being humidified and supplying fluid at a variable pressure in accordance with the humidity in the area being humidified, and fluid pressure responsive means controlled by said humidistat means for moving said valve slide to a fully open position or to a partly open position in accordance with the humidity in the area being humidified, whereby the flow of steam to said steam disperser is modulated i accordance with the humidity in the area being humidified.

2. A device as defined in claim 1, including a generally flat valve seat in said inner casing surrounding said port, and wherein said valve slide slides across said valve seat between its open and closed positions, said valve slide being held in sealing engagement with said valve seat in the closed position by the pressure of steam seeking to enter said exit chamber.

3. A device as defined in claim 1 wherein said outer casing has a condensate drain in the bottom thereof, and a valve in said steam entry chamber for opening said drain to release condensate collected in the bottom of said chamber, said valve having a float operatively connected thereto to open said valve in response to the buoyant force caused by the collection of sufficient condensate in the bottom of said entry chamber.

4. A device as defined in claim 1 wherein said fluid pressure responsive means for moving said valve slide comprises a fluid cylinder, a piston in said cylinder, operatively connected to said valve slide, a spring biasing said piston to a position wherein said valve slide is in its closed position, fluid pressure supplied by said humidistat means acting on said piston, in a direction tending to counter the force of said spring an amount depending upon the humidity in the area being humidified.

5. A device as defined in claim 4 including externally accessible means for adjusting the tension in said spring. 6. A device as defined in claim 4 including externally accessible means for limiting the movement of said piston in a direction tending to open said port, whereby to limit the maximum opening between said valve slide and said port.

7. A device for controlling steam passage from a steam supply line to a steam disperser in a humidification system which uses steam as an air moistening agent, comprising an outer casing defining a high pressure steam entry chamber communicating with the steam supply line, an inner casing within said entry chamber and defining a lower pressure steam exit chamber communicating with the steam disperser, said inner casing having a valve port communicating between said inlet chamber and said exit chamber, means forming a generally flat valve seat in said outer chamber surrounding said valve port, a valve slide adapted for linear movement on said valve seat between a position completely or partly opening said port and a position closing said port, humidistat means for sensing the humidity in an area being humidified and supplying fluid at a variable pressure in according with the humidity in the area being humidified and fluid pressure responsive means controlled by said humidistat means for moving said valve slide in response to the relative humidity in the are being humidified by steam from said disperser. 

1. A device for controlling steam passage from a steam supply line to a steam disperser in a humidification system, comprising an outer casing defining a high-pressure steam entry chamber communicating with a steam supply, an inner casing within said entry chamber and defining a lower pressure steam exit chamber communicating with the steam disperser, said inner casing having a valve port communicating between said inlet chamber and said exit chamber, a valve slide adapted for linear movement in said entry chamber to open and close said port, humidistat means for sensing the humidity in an area being humidified and supplying fluid at a variable pressure in accordance with the humidity in the area being humidified, and fluid pressure responsive means controlled by said humidistat means for moving said valve slide to a fully open position or to a partly open position in accordance with the humidity in the area being humidified, whereby the flow of steam to said steam disperser is modulated i accordance with the humidity in the area being humidified.
 2. A device as defined in claim 1, including a generally flat valve seat in said inner casing surrounding said port, and wherein said valve slide slides across said valve seat between its open and closed positions, said valve slide being held in sealing engagement with said valve seat in the closed position by the pressure of steam seeking to enter said exit chamber.
 3. A device as defined in claim 1 wherein said outer casing has a condensate drain in the bottom thereof, and a valve in said steam entry chamber for opening said drain to release condensate collected in the bottom of said chamber, said valve having a float operatively connected thereto to open said valve in response to the buoyant force caused by the collection of sufficient condensate in the bottom of said entry chamber.
 4. A device as defined in claim 1 wherein said fluid pressure responsive means for moving said valve slide comprises a fluid cylinder, a piston in said cylinder, operatively connected to said valve slide, a spring biasing said piston to a position wherein said valve slide is in its closed position, fluid pressure supplied by said humidistat means acting on said piston, in a direction tending to counter the force of said spring an amount depending upon the humidity in the area being humidified.
 5. A device as defined in claim 4 including externally accessible means for adjusting the tension in said spring.
 6. A device as defined in claim 4 including externally accessible means for limiting the movement of said piston in a direction tending to open said port, whereby to limit the maximum opening between said valve slide and said port.
 7. A device for controlling steam passage from a steam supply line to a steam disperser in a humidification system which uses steam as an air moistening agent, comprising an outer casing defining a high pressure steam entry chamber communicating with the steam supply line, an inner casing within said entry chamber and defining a lower pressure steam exit chamber communicating with the steam disperser, said inner casing having a valve port communicating between said inlet chamber and said exit chamber, means forming a generally flat valve seat in said outer chamber surrounding said valve port, a valve slide adapted for linear movement on said valve seat between a position completely or partly opening said port and a position closing said port, humidistat means for sensing the humidity in an area being humidified and supplying fluid at a variable pressure in according with the humidity in the area being humidified and fluid pressure responsive means controlled by said humidistat means for moving said valve slide in response to the relative humidity in the are being humidified by steam from said disperser. 